With frequent writes, solid-state drives (SSDs) including flash drives may have a quicker End of Life (EOL) due to limited endurance compared to hard disk drives (HDDs). Once an SSD reaches EOL it can no longer accept requests from the host and needs to be replaced.
Because SSDs are typically faster than HDDs, SSDs are found in some data storage systems as caching devices. A number of SSDs may be installed in a disk array enclosure to form an array that can be used as a cache tier or a hot add tier to improve the performance of the data storage system.
There is a likelihood that all or a majority of SSDs within a cache tier array may reach their EOL at approximately the same time, especially when they were installed at the same time and the write loads have been similar. When this happens, the overall performance of the data storage system may suffer, because no more SSD space is available for caching, until the SSDs that have reached EOL have been replaced.